This invention relates to improvements in the communication of audio signals over AC power and wiring lines by which stereophonic signals may be transmitted from, for example, hi-fidelity audio equipment to loudspeakers.
Typical wireless intercom systems utilize AM transmission techniques for voice communication over AC wiring lines. AC wiring in most households are subjected to electromagnetic noise from many sources, particularly impulse noise or noise spikes from SCR or triac circuits of the type normally found in lamp dimmers. As a result, AM signals transmitted over such lines may be so degraded that the information contained therein is not comprehensible when received. It also has been found that in some environments, impulse noise and so-called dimmer interference may be picked up by the FM wireless speaker system disclosed in application Ser. No. 053,355.